[Tile-serving] Switch2osm rewrite review needed

[Frederik Ramm]

Hi,

On 10.05.2014 09:34, Paul Norman wrote:
> I am quite confident that the command lines given are accurate. Where review
> is more useful is the text explaining them, particularly around the
> osm2pgsql command line.

Couple thoughts, ignore at will:

* s/strongly not recommended/strongly discouraged/

* some of your apt-get lines have backslashes when line-wrapping, some
don't; I'd drop them all

* generally I would try to keep all commands as simple as possible - we
do not want to condition users to blindly type stuff they don't
understand. This starts with "sudo apt-get update && sudo apt-get -y
upgrade" (why introduce the cryptic && here - simply do two lines) but
goes on; do we need "--no-install-recommends", will the stuff that is
installed additionally really be such a burden? Should we have people
blindly execute "sed -i "s|Allow from.*|Allow from all|"
/etc/munin/apache.conf" without even telling them what it is for or at
least warning them that it might have side effects?

* I am not comfortable with elevating osmctools to the mainstream (were
they in switch2osm.org before?) but that might be a personal bias - I'm
just so used to Osmosis and consider Osmosis the standard tool for
updating. You also mention osmconvert for creating extracts but

* Is this overcommit thing a new requirement under Ubuntu 14.04? Because
I've certainly never fiddled with it yet, and I run many a tile server.
If it isn't essential, drop it.

* osm2pgsql command line - suggest to use long flags throughout (no -C,
-S) for clarity; suggest to drop --create

* s/minimal gains/only minimal gains/

* punctuation in the list that explains the osm2pgsql options - either
use a full stop on all of the list elements or none?

* "anywhere from seconds for Liechtenstein" - I'd rather write "minutes"
and risk people being positively surprised if they are on a fat machine ;)

* For --hstore, you write "very minor speed penalty" but you should also
mention a +10% size penalty on average. If you're doing an import for an
area with lots of source/note/whatever tags then it can be significantly
more - for example, a full --slim import for Japan takes 19 GB without,
and 25 GB with -k (these numbers being the total amount of disk storage
used by the PostGIS tablespace). As a side note, this is also where
--hstore-match-only comes into play; a standard import of Japan has
1058397 records in planet_osm_point while a -k import without
--hstore-match-only has 3452629 due to there being many nodes with
"un-interesting" tags only. Same figures for planet_osm_line are less
drastic (7050958 vs 7224628) - just mentioning it because you recently
doubted the usefulness of --hstore-match-only.

* Please don't write "design beautiful maps with TileMill", that's
advertising. "Design your own maps with TileMill" is correct - whether
they turn out ugly or beautiful has nothing to do with the tool you're
using.

Bye
Frederik

-- 
Frederik Ramm  ##  eMail frederik at remote.org  ##  N49°00'09" E008°23'33"